CAPE CANAVERAL, Fla. -- Towed by tugboats, the Pegasus barge with its cargo of external tank 130 nears the dock in the turn basis near the Vehicle Assembly Building, or VAB, at NASA's Kennedy Space Center in Florida. Pegasus arrived in Florida after an ocean voyage towed by a solid rocket booster retrieval ship from NASA's Michoud Assembly Facility near New Orleans. After the Pegasus docks, the fuel tank will be offloaded and transported to the VAB. External tank 130 is the one designated for space shuttle Endeavour on the STS-127 mission targeted for launch on May 15. Photo credit: NASA/Troy Cryder KSC-08pd3899

The Space Shuttle program was the United States government's manned launch vehicle program from 1981 to 2011, administered by NASA and officially beginning in 1972. The Space Shuttle system—composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank— carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). When its mission was complete, the orbiter would re-enter the Earth's atmosphere and lands as a glider. Although the concept had been explored since the late 1960s, the program formally commenced in 1972 and was the focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. It started with the launch of the first shuttle Columbia on April 12, 1981, on STS-1. and finished with its last mission, STS-135 flown by Atlantis, in July 2011.